1. Field of the Invention
This invention relates to a biological air filter, having a generally cylindrical filter housing capable of receiving water and/or a liquid nutrient, and at least one filter element including a plant pot with a substrate and at least one plant, contained in the housing, wherein air is circulated through the filter element.
2. Description of Prior Art
Many conventional air cleaning and humidifying devices use purely physical or physio-chemical methods which generally require expensive filter elements. These dry or wet filter systems are often an ideally suited nutritive medium for breeding many various types of germs. A somewhat turbulent air flow at the outlet also causes the germs to be carried along and discharged into the room air.
It is known from "Interior Landscape Plants For Indoor Air Pollution Abatement", Final Report--Sept. 1989, B.C. Wolverton, Anne Johnson and Keith Bonds, NASA Report MS 39529-6000, that plants can absorb and metabolize various types of airborne harmful substances. Plants growing in a substrate containing activated charcoal are able to regenerate air containing harmful substances through their roots using a bio-regenerative process and can absorb the harmful substances with the aid of soil bacteria. This bacterial soil life is also capable of destroying pathogenic germs which may be present. The invention can be described as a plant pot in which plants grow on a bed of activated charcoal. The pot is mounted in a container having a blower which blows air upward through the air-permeable but water-nonpermeable bottom of the pot and through the substrate containing activated charcoal. A system which directs excess water from the plant pot into an overflow container is also provided.